Gas mixer



April 12, 1955 WARD 2,705,996

' GAS MIXER Filed March 15, 1954 JNVENTOR.

United States Patent GAS MIXER Mark E. Ward, Columbus, l1io, assignor to Surface Combustion Corporation, Toledo, Ohio, a corporation of Ohio Application March 15, 1954, Serial No. 416,255

3 Claims. (Cl. 158118) This invention relates to gas mixers of the type where a jet of fuel gas from a nozzle is directed into the mouth of a mixing tube in a manner to entrain primary air, mixers of this type being commonly employed with gas burners.

This application is a continuation-in-part of application Serial No. 221,643 filed April 18, 1951, and now Patent No. 2,675,869.

It is well known that air in a dwelling contains lint and that in course of time this lint tends to clog an ordinary air shutter for a gas mixer such as, for example, a rotary type air shutter. An object of the present invention is to provide an air shutter of a type that lint in the air cannot readily clog.

For a consideration of what I believe to be novel and my invention, attention is directed to the following portion of the specification, the drawing, and the concluding claims.

In the drawing:

Fig. 1 is a side elevation with ratus for the present invention.

Fig. 2 is a sectional view on line 22 of Fig. 1.

Fig. 3 illustrates a modified form of the apparatus.

Fig. 4 is a sectional view on line 44 of Fig. 3.

Fig. 5 illustrates another modified form of the apparatus.

Fig. 6 illustrates another modified form of the apparatus.

The apparatus with which the present invention has special utility comprises a mixing tube generally indicated at 10, the same being slidably supported in a conduit 11 leading to a burner 12, the conduit being shown as supported on a bracket 13 on a base member 14. The throat of the mixing tube is indicated at 15, the same having a flaring mouth 16. A nozzle for directing a stream of fuel gas into said throat 15 is indicated at 17, the same being mounted in the front end wall 18 of a hollow head or fitting 19 to which gas under pressure is delivered by a supply pipe 20, the head being shown as supported on a bracket 21 mounted on the base members 14.

For reasons presently appearing, the external diameter of the hollow head 19 is such that a substantial portion of its length from the leading face 22 of the end wall 18 is adapted to be telescopically received, like a piston, by the leading end of the throat 15, the range of axial adjustment of said tube being such that it may be backed away from the leading peripheral edge of said face 22 to provide an air gap of substantial size for the admission of a relatively large quantity of air to the mixing tube depending on the kind of fuel being used. On the other hand, where the quantity of air required to be admitted to said throat is so small that the leading peripheral edge of said face 22 and of said throat would have to be objectionably close together from the standpoint of linting, the present invention, as will presently appear, provides a relatively unrestricted air inlet port whose effective size may be readily adjusted by varying the distance to which the leading edge of face 22 extends into said throat 15.

In the apparatus shown in Fig. 1, the relatively unrestricted air inlet port for relatively small quantities of air is generally indicated at 23, the same being formed by a notched or slanting portion 24 on the leading face 22 of said end wall 18 in a direction away from said throat, the slant being shown as beginning at a line or chord parts in section of appabelow the nozzle 17. It will be readily appreciated that the effective size of said port 23 can be varied as desired by varying the degree to which the leading peripheral edge of said face 22 extends into said throat 15. This form of the apparatus is the subject of said application Serial No. 221,643.

In the form of the apparatus shown in Fig. 3, the leading face of the front end wall of the head 19 is identified by reference numeral 25, the entire surface of said face 25 being in a common plane in contra-distinction to the face 22 in Fig. 1 which has the slanting portion 24. In Fig. 3, the side wall of the throat 15 is provided with a triangular aperture 26, preferably having rounded corners whose apex is down stream from the leading edge of said throat. When the leading peripheral edge of said face 25 is telescopically received by the leading edge or end of the throat 15, said aperture serves as a relatively unrestricted port for the admission of air to the mixing tube, and since the mixing tube is axially adjustable relative to said face 25, the effective size of said port may be varied as desired as will now be readily understood,

In Fig. 5 an alternate shutter for the apparatus of Fig. 3 comprises a tube 15 having a-leading flared edge 16 and a substantially V shape aperture 35 therein whose apex is ggwnstream from the leading edge of the throat, or tube In Fig. 6 another alternate shutter 15 is shown having a leading, flared edge 16 in a plane inclined to the axis of the tube 15, and another alternate nozzle is indicated at 17 mounted on the front end wall of a hollow head 28 having a cylindrical flange 27 whose leading edge 29 lies in a plane inclined to the axis of the flange 27 and to the plane of the leading edge 16 of the tube 15. Fuel gas is supplied through pipe 20 to the nozzle 17, and upon issue therefrom it entrains air through the air inlet port formed between the leading edges of the nozzle and the tube. When the air inlet port is partially closed the cylindrical surfaces of the tube 15 and the flange 27 of the nozzle 17 form a discontinuous area of contact defining at the discontinuity a relatively wide, unrestricted air inlet port; the nozzle and tube thus forming a nonlinting air shutter.

From the foregoing it is believed to be apparent that the present invention provides an air shutter that is well adapted for its intended purpose.

I claim:

1. In a gas mixer formed by members comprising a nozzle for discharge of gas into a conduit and an axially movable mixing tube forming part of said conduit and adapted to move toward and telescope over said nozzle to close a variable air inlet port to the conduit between said nozzle and said tube, the improvement wherein said members each comprise a cylindrical surface around the periphery of said members and the leading edge of one of said members lies in a plane inclined to the plane of the leading edge of the other of said members, whereby to form a discontinuous contact area between said cylindrical surfaces when said variable air inlet port is partially closed, said port then being a relatively wide, unrestricted air passage at said discontinuity.

2. In a gas mixer according to claim 1, the improvement wherein the leading edge of the cylindrical surface of the nozzle lies in a plane perpendicular to the axis of said surface and the leading edge of the cylindrical surface of the tube lies in a second plane inclined to said first mentioned plane.

3. In a gas mixer according to claim 1, the improvement wherein the leading edge of the cylindrical surface of the tube lies in a plane perpendicular to the axis thereof, and the leading edge of the cylindrical surface of the nozzle lies in a second plane inclined to said first mentioned plane.

References Cited in the file of this patent UNITED STATES PATENTS 

